Solan Bank Reef MPA

Please be advised, a consultation has begun by Scottish Government on fisheries management measures within Scottish MPA. This will run until 14 October 2024. For more information please visit the Scottish Government website.

 

Status: Special Area of Conservation (SAC)

Solan Bank Reef is located 50 km from the Scottish mainland, north of Cape Wrath. The reef is situated on a geological feature known as 'Solan Bank High'.

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Site Timeline

The diagram below is a summary of the key milestones involved in the selection and designation of Solan Bank Reef SAC. More detail can be found in the Relevant Documentation section.

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Relevant Documentation

The documents referred to below and any other historical documents relating to Solan Bank Reef were produced during the selection and designation process and therefore may be out of date.  This Site Information Centre is the most up-to-date source of information for this MPA, and will reflect any additional information gathered since these documents were produced. Information about the SAC site selection process is available on JNCC's SAC webpages.

• Standard Data Form – Details of the SAC and the designated features.
• SAC Selection Assessment Document – Overview of the SAC, designated features and rationale for site selection.
• Conservation Objectives and Advice on Operations – Information about feature sensitivity, vulnerability and risk and the Conservation Objectives for the designated features of the site.
• Management Options Paper – Considers the management options for achieving the conservation objective for the protected feature in the MPA.
• Post-consultation Report and Impact Assessment – Overview of the consultation outcomes, and an assessment of the environmental, social and economic costs and benefits of the designation.

These resources are available on JNCC's Resource Hub.

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Summary

Last updated: October 2017

Information for this site summary was adapted from the SAC Selection Assessment Document and incorporates any further information gathered since these documents were produced. Please refer to this document in the Relevant Documentation section for further details and information sources. 

 

Site Overview

Solan Bank Reef SAC is located approximately 50 km from the Scottish mainland, north of Cape Wrath. The reef is located on the Solan Bank High, a Precambrian geological feature of metamorphic basement rock 130 km long and 25 km wide with sections of sand and clay. The site is surrounded by the North Rona, North Lewis, North Minch and West Orkney basins and between the East Rona High to the west and Nun Rock-Sule Skerry High to the east. The majority of the site lies in water depths of 60–80 m. However to the south-east of the site an outcrop of bedrock reef rises to approximately 20 m below the sea surface, while the north of the site extends to more than 90 m water depth.

The site represents the Annex I reef sub-types 'bedrock' and 'stony' reef. Bedrock outcrops create areas of high topography, with linear features (thought to be bedrock joint planes) forming cliffs of up to 10 m in height above the surrounding seabed. Elsewhere the bedrock forms smooth and undulating features known as roches moutonnées, created by the scour effect of moving glacial ice. Stony reef comprised of boulders and cobbles with a sandy veneer occurs in ridges to the north-west and south-west of the site; these most likely represent glacial moraine ridges (the tracks of sediment carried by glacial ice). Boulders and cobbles also occur in the larger crevices in the bedrock while smaller rock fissures are filled with a mixture of coarse sand and shell/gravel veneer. A veneer of sand occurs over the flat bedrock surfaces, indicating that sediment scour is a significant factor across the site.

The reefs are characterised by encrusting fauna, mainly encrusting bryozoans and encrusting coralline algae in the shallower areas. Cup corals are present throughout the site, and brittlestars are common on both the bedrock and stony reef. Areas of flatter bedrock subject to sediment scour have a lower diversity of fauna than more sheltered areas. The highly scoured reef is mainly colonised by the keel worm Pomatoceros triqueter, while a range of sponges, bryozoans and hydroids occur on less scoured reef areas. Water movement created by tidal streams and wave action is greater in shallower areas and here there is a higher abundance of species such as the soft coral Alcyonium digitatum, the cup coral Caryophyllia smithii and the jewel anemone Corynactis viridis. Foliose red algae and kelp grow in the shallowest locations where light penetrates the water.

Annex I reef habitat is also protected in the nearby North Rona SAC (in Scottish territorial waters) where a variety of rock habitats from the intertidal (littoral) through to 50 m depth (deep circalittoral) occur. These reefs support rich marine communities typical of rock exposed to high wave energy. Further detail on the evidence for this SAC can be found in the Monitoring and Evidence section.

Site location: Co-ordinates for this SAC can be found in the Standard Data Form listed in the Relevant Documentation section.

Site area: 856 km².

Site depth range: 20 m at the top of the reef feature, to 140 m below sea-level at the base of the Solan Bank High geological feature, but the site mostly lies between 60 m and 80 m below sea-level.

Charting Progress 2 Biogeographic Region: Scottish Continental Shelf.

Site boundary description: The site boundary for Solan Bank Reef SAC has been defined using JNCC’s marine SAC boundary definition guidelines. The boundary is a relatively simple polygon enclosing the minimum area necessary to ensure protection of the Annex I habitat. As any bottom trawling that occurs in the area may pose a threat to the reef, the site boundary includes a margin to allow for mobile gear on the seabed being at some distance from the location of a vessel at the sea surface. The maximum depth of water around the feature is approximately 100 m; assuming a ratio of 3:1 fishing warp length to depth on the continental shelf, the boundary is defined to include a margin of 300 m from the bedrock and stony reef feature.

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Monitoring and Evidence

Last updated: November 2023

The full overview of the data used to support site identification along with information on confidence in feature presence and extent is available in the Solan Bank Reef SAC Selection Assessment Document. JNCC will be adding relevant survey data for this MPA to its MPA Mapper in due course.

Some of the data for this SAC have been collected through JNCC-funded or collaborative surveys and some through other means. Data from this survey provide direct evidence confirming the presence of the protected feature within the site. 

 

Survey and data gathering

• Solan Bank Reef SAC survey (2014) – JNCC commissioned a survey to gather seabed evidence to inform development of a national indicator of 'Good Environmental Status' for sponge and other epifaunal communities as part of the UK’s obligations under the Marine Strategy Framework Directive (MSFD). The survey, undertaken by Marine Scotland Science, obtained photos and video footage from reef and non-reef habitats within the site and conducted assessments of the number of sponges and their body shapes (morphologies). The JNCC survey blog provides an account of this survey.
• Mid-Irish Sea and Solan Bank survey (2008) – JNCC commissioned a survey carried out by Cefas investigating the Annex I reef feature characteristic of Solan Bank Reef as well as submarine structures in the mid-Irish Sea. This survey helped to characterise the biological communities associated with the Annex I reef feature in Solan Bank Reef, and identified encrusting fauna (bryozoans and corallines), an unusual cup coral and rare sponges.

 

Data analysis reports

• Analysis of epibenthic and environmental data from Solan Bank Reef (2016) – Identified the epibenthic assemblages of Solan Bank Reef and the environmental factors influencing their distribution. Videos and photographs were analysed from 166 drop-frame camera sampling stations taken on the 2014 survey. Bedrock and stony reef habitats had more species than surrounding habitats such as coarse and mixed sediments, but the number of species was similar between bedrock reef and stony reef. Seabed sediment composition, water depth and temperature were most influential on the distribution of epibenthic assemblages; sponges and anthozoans in particular were also influenced by current velocity and bottom shear stress. The study also tested subsets of the epibenthic dataset to see if they could be used as surrogates for the whole dataset. A dataset comprising of sponges classified by morphological categories predicted similar patterns in overall epibenthic assemblage composition compared to the full epibenthic dataset, suggesting sponge morphologies could have use as an indicator of biodiversity.
• Analysis of seabed video and photographic footage from Solan Bank Reef (2016) – Analysed images from 166 drop-down camera transects taken during the 2014 survey made 17,500 observations of 320 different taxa. Bryozoans, echinoderms and worms were most frequently observed (31%, 14% and 12% of observations respectively), while forty-two percent of the organisms were formed of crusts on the seabed. Over 90% of transects contained one or more types of sponge morphology, with encrusting, massive and flabellate sponges being the most common. Species of conservation interest included whiting Merlangius merlangus, cod Gadus morhua, ling Molva molva and benthic epifauna such as northern feather star Leptometra celtica and white cluster anemone Parazoanthus anguicomus. Stony or bedrock Annex I reef was observed with medium or high confidence in approximately one-third of transects, depending on analysis using photographic stills (34% of transects) or video footage (28%). Evidence of human activity was found at eight transects, including litter and fishing gear. The study also compared methods for identifying and counting sponges and found that dividing and analysing videos by natural breaks in habitat was more than two times quicker than dividing footage into 20 second segments, and five times quicker than dividing footage into 10 second segments.
• Habitat mapping of MPAs in Scottish waters based on acoustic interpretation (2014) – Multibeam and backscatter acoustic datasets were collated by Sotheran and Crawford-Avis (2014) to generate seabed habitat maps, including the far north of Solan Bank Reef where coarse sediments were predicted. This JNCC-commissioned project used Civil Hydrography Programme and Maritime and Coastguard Agency datasets, processed by the National Oceanography Centre and interpretated by the British Geological Survey.
• Seabed habitat investigations in the mid Irish Sea and Solan Bank (2010) – Acoustic, photographic, video and grab sample data collected as part of the 2008 JNCC survey to Solan Bank Reef were analysed to determine the topographic, substrate and biological characteristics of the Solan Bank Reef. Substrates varied from well-sorted sands through to creviced bedrock, and the Annex I reef feature was found to comprise both bedrock and stony reef. The majority of the reef was characterised by encrusting fauna, particularly bryozoans and corallines in shallow areas.  

 

Additional relevant literature

References for further supporting scientific literature consulted during the identification of this site can be found in the Solan Bank Reef SAC Selection Assessment Document. Please be aware that although these sources contain information in relation to this MPA, they do not necessarily represent the views of JNCC. 

 

Knowledge gaps

As part of the UK Marine Monitoring and Assessment Strategy (UKMMAS), JNCC led the development of a UK Marine Biodiversity Monitoring Strategy, working with partners across the UK monitoring community. The Strategy spans UK territorial and offshore waters, focusing on biodiversity in the wider environment and within Marine Protected Areas.  Its aim is to implement efficient, integrated monitoring of marine biodiversity to provide the evidence needed for all the UK's policy drivers.

The Marine Directorate of Scottish Government, in partnership with JNCC and NatureScot, developed a Scottish Marine Protected Area (MPA) monitoring strategy. The Strategy spans Scottish territorial and offshore waters, focusing on biodiversity within Marine Protected Areas. The Strategy is supported by a series of annexes which provide more detail on monitoring methods, collaborative working, current monitoring and a two year forward look for MPA monitoring in Scottish waters.

The evidence collected during MPA monitoring surveys is used in combination with other available evidence to:

• Enable assessment of condition of the features within sites;
• Contribute to the assessment of the degree to which management measures are effective in achieving the conservation objectives for the protected features;
• Support the identification of priorities for future protection and/or management; and,
• Enable Government to fulfil its national and international assessment and reporting commitments in relation to MPAs and help identify where further action may be required.

More detail on offshore MPA monitoring can be found on the Offshore MPA monitoring webpage. A list of monitoring surveys and relevant reports can be found on the MPA monitoring survey reports webpage.

If you are aware of any additional information not referred to above or in the Relevant Documentation section, please contact us. 

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Conservation Advice

Last updated: November 2023 

Conservation objectives

Conservation objectives set out the desired state for the protected feature(s) of an MPA. The conservation objectives for the protected feature of the Solan Bank Reef SAC has been set based on knowledge of the condition of the protected feature at the time of writing. Further information on feature condition and conservation objectives is provided in the Solan Bank Reef Conservation Objectives and Advice on Operations Document.

This information is useful if you are:

• Preparing Habitats Regulations Assessments (HRAs) of proposed plans or projects that may affect the site;
• Planning measures to maintain or restore the site and its qualifying feature;
• Monitoring the condition of the qualifying feature; and/or
• Developing, proposing or assessing an activity, plan or project that may affect the site.

 

Advice on operations

In line with Regulation (21) of The Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended) which apply to the UK’s offshore marine area, and Regulation 33(2) of Habitats Regulations 1994 (as amended in Scotland), which apply to Scotland’s inshore waters, the advice on operations for the protected feature of the Solan Bank Reef SAC outline current knowledge of the nature and extent of activities taking place which may have a significant impact on the feature for which a site has been selected.

The advice on operations is based on the scientific knowledge of JNCC and Scottish Natural Heritage (now NatureScot) on the biological communities present at the time of writing and their sensitivities to pressures. For the most up-to-date information about the biological communities present within the site and their spatial distribution, please see the Monitoring and Evidence section. Sensitivity information for biological communities identified within the site can also be found on the MarLIN website.

The information contained within the advice on operations, Monitoring and Evidence section, and MarLIN’s sensitivity assessments are useful if you are:

• Carrying out any activity that may impact the site and need to find out how to operate within the law;
• An authority providing advice on specific proposals; and/or 
• An authority responsible for putting management measures in place.

Our scientific understanding of the ecology of the site, its integrity and its qualifying feature and how activities can affect them may change over time. Conservation advice provided by JNCC and Scottish Natural Heritage (now NatureScot) will be kept under review and will be periodically updated to reflect this. Conservation advice for sites which straddle the 12 nm boundary will continue to be developed jointly with the relevant country nature conservation body. Further information on JNCC’s conservation advice work is available on our 'Conserving MPAs' webpage.

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